WASHINGTON — Massachusetts Rep. Seth Moulton, a Marine veteran and Democratic leadership critic, is running for president, he announced Monday.

Moulton made his announcement in a video Monday morning, saying: "I'm running because we have to beat Donald Trump, and I want us to beat Donald Trump because I love this country. We've never been a country that gets everything right. But we're a country that, at our best, thinks that we might."

Moulton joins a packed field of roughly 20 Democrats who are vying for the opportunity to run against President Donald Trump and could potentially make the early debates. Ahead of him are other current and former House candidates, other veterans, and another member of the Massachusetts delegation.

"I'm not a socialist, I'm a Democrat," Moulton said in an interview Monday morning with Good Morning America. "And I want to make that clear. And maybe that's a differentiator for me in this race."

He is best known for his involvement in an unsuccessful coup to prevent Nancy Pelosi from once again becoming the speaker of the House when Democrats returned to the majority after last year’s midterms. Ohio Rep. Tim Ryan, who is also running for president, was also involved in the efforts. Ultimately, what started off as calls for a “new generation of leadership” came to be seen as attacks tinged with sexism and ageism.

There’s long been talk of Moulton’s presidential aspirations — former president Barack Obama invited him to discuss a run, Moulton has said — and his decision has been anticipated since February, when BuzzFeed News first reported he was thinking seriously about running. His decision, he said then, would hinge at least in large part over whether to put his family through a rigorous primary.

He’ll now also have to play catchup in the race, including ensuring that he qualifies for the debates by either raising money from 65,000 people in a total of 20 states or by reaching 1% or more in at least three polls.

The young congressman initially stood out for his penchant for criticizing Democratic leadership. He arrived to his congressional seat by ousting a Democrat in a primary, immediately upsetting some in the party establishment and forcing him to learn to make his own way.

Since then, he’s earned himself a reputation as a solid fundraiser and has served as a mentor to Democratic candidates, particularly veterans.